Toyota: advice on 12v battery maintenance

[AisinW]

It is a simple batch of bad 12V Battery. Nothing dramatic, just replace the 12V with a good one and you are good to go. Besides that, you have free towing service for a new car. Toyota recently outsource many Battery from other manufacturers beside Yuasa or Panasonic. Or maybe Yuasa made bad batches.

It is not leaky water pump like 2.0 TSI, timing chains wear, injectors, fuel pump, or turbo issues that cost a lot of time and money. 

The most common cause of degrading 12V AGM Battery is leaving it depleted. Once it happens, the damage is done, the 12V battery is permanently damaged. Watch out to accesories like Dashcam, etc. It often cause died battery.

[AisinW]

If you want to buy charger, get the one with controller like CTEK 5 or NOCO Genius 5 not cheapest one like the video below that will destroy the Battery instead. It does not really do automatic charging properly with steps voltage and amperage. 

  

[AisinW]

Toyota TSB about charging 12V Battery or leaving cars for 10 days.  https://priuschat.com/attachments/auxbattery_204-pdf.1634/

Generally we must charge it when the Battery is disconnected from the car. Never use non AGM Battery in Prius. For storing more than 10 days remove D/C Cut fuse or remove the connector on the relay  box. 

If it is not driven after 2 months, we need to charge the HV battery too by turning it on for 30 minutes.

I think turning the car on every 10 days is the best way because a good 10A charger is expensive. 

[Catlover]

Why “Never use non AGM Battery in Prius” ?

[Roy124]

AisinW. If I had to do that to keep my car running I would never buy that model. 

With service intervals between 6,000 and 12,000 miles who would consider a 1 000 or 3000 interval today. 

[Cyker]

Safety, and charge cycle probably; flooded cells and AGM use different charge cycles and don't like being charged the other way (flooded cells like to be float-charged, but AGM cells much prefer cyclic charging. Using the wrong cycle tends to make them off-gas and swell up, or degrade faster)

Some Toyotas can be a bit of a PITA for 12v batteries - All the in-cabin ones have vent tubes that standard batteries that go in the engine bay don't have.

[FROSTYBALLS]

4 hours ago, AisinW said:

https://priuschat.com/attachments/auxbattery_204-pdf.1634/

The TSB linked to dates back to October 2003, and relates to the 2004-05 Prius. Hardly applicable to hybrids in production 19 years later.  I do wish that more attention is given to when things are written, whether it is TSB, topics, etc, and whether they apply to current models

[AisinW]

6 minutes ago, Roy124 said:

AisinW. If I had to do that to keep my car running I would never buy that model. 

With service intervals between 6,000 and 12,000 miles who would consider a 1 000 or 3000 interval today. 

Run it once a month for 30 minutes is important for any car to keep the engine lubricant coat all metal surface. Valve train, piston rings, and piston can get corroded if it is not coated.  My old mechanics told me to squirt some oil on my 02 Altima when the headgasket leaks and parked for few weeks until i have money to repair it. 

[AisinW]

15 minutes ago, FROSTYBALLS said:

The TSB linked to dates back to October 2003, and relates to the 2004-05 Prius. Hardly applicable to hybrids in production 19 years later.  I do wish that more attention is given to when things are written, whether it is TSB, topics, etc, and whether they apply to current models

2nd and 3rd gen/auris has exchangeable Battery cells with similar system. DC to DC converter charge the Battery from HV Battery, not the engine. It is still applicable. The 4th gen is still similar too in terms of 12V battery and NiMh battery. Even the 12V battery are identical. 

[Roy124]

6 minutes ago, AisinW said:

Run it once a month for 30 minutes is important for any car to keep the engine lubricant coat all metal surface. Valve train, piston rings, and piston can get corroded if it is not coated.  My old mechanics told me to squirt some oil on my 02 Altima when the headgasket leaks and parked for few weeks until i have money to repair it. 

I agree with that but not any of the detail in your original post, ie disconnecting the Battery, removing fuses and having to charge the HV Battery after 2 months. 

If the car is laid up then of course I would expect some work to return it to the road. 

[AisinW]

D/C  cut fuse is the only source of current drawn when the car is off. It controls the car body and remote keys. If that fuse is removed, practically all are mechanical including opening the doors and no light can be on. 

Updated TSB 2014 for 3rd and 4th gen hybrid https://m.carcomplaints.com/Toyota/Prius/2015/tsbs/tsb-t-sb-0087-14-rev.shtml

The difference is 30 days limit instead of 10 days for removing the Battery connection. I believe the 2nd gen smart key is not that smart and 3rd gen has better power management for smart  Battery. 

30 mins runs is sufficient to charge the HV and 12V batterries in hybrid every 2 months. 

[AisinW]

https://m.carcomplaints.com/Toyota/Prius/2020/tsbs/tsb-t-sb-0006-19.shtml

for 2020 TSB hybrid. Similar to 3rd gen Prius. 30 days off is the limit for removing the Battery terminal. I believe removing negative terminal is easier for most people than removing 30A D/C cut fuse. It also guarantees no external current at all. 

For me, it is easier pulling 30A fuse under the hood instead of Battery terminal in the trunk. Especially, if we have  no garage and must close the rear hatch. 

[Roy124]

Question for all you converts that use a CTEK charger or equivalent, even if you are using the car regularly, do you also use the CTEK for conditioning? 

[preperationlaunch]

I've had my first flat Battery in a long time in a car with my Hybrid Yaris today.

I turned it on, noticed it took longer than usual to go into ready, and the wiper which came on with the ignition crawled across the screen in slow motion.

It's almost certainly the original Battery which is nearly 5 years old and it is currently on charge all day on the CTEK in AGM mode, so I expect it'll be fine.

The upside to using a charger like the CTEK is it's smarter than the DC-DC converter for things like desulfation.

On 1/11/2022 at 7:37 PM, AisinW said:

https://m.carcomplaints.com/Toyota/Prius/2020/tsbs/tsb-t-sb-0006-19.shtml

for 2020 TSB hybrid. Similar to 3rd gen Prius. 30 days off is the limit for removing the battery terminal. I believe removing negative terminal is easier for most people than removing 30A D/C cut fuse. It also guarantees no external current at all. 

For me, it is easier pulling 30A fuse under the hood instead of battery terminal in the trunk. Especially, if we have  no garage and must close the rear hatch. 

How many insertion cycles is the D/C cut fuse rated for though? My worry would be if you're doing that regularly, you're liable to cause undue wear.

[IanML]

19 minutes ago, Roy124 said:

Question for all you converts that use a CTEK charger or equivalent, even if you are using the car regularly, do you also use the CTEK for conditioning? 

I have too many cars, so they don't get used enough.  I use the CTEK for periodic recharging, and, if I see a drop-off in SOH (using a Battery condition meter) I perform a recon cycle, which does improve the SOH.   I probably do a recon one charge in three.

[Roy124]

Ian, I was thinking much more for people perhaps using their car for a daily commute, say 10 miles a journey. 

[AisinW]

2 hours ago, preperationlaunch said:

I've had my first flat battery in a long time in a car with my Hybrid Yaris today.

I turned it on, noticed it took longer than usual to go into ready, and the wiper which came on with the ignition crawled across the screen in slow motion.

It's almost certainly the original battery which is nearly 5 years old and it is currently on charge all day on the CTEK in AGM mode, so I expect it'll be fine.

The upside to using a charger like the CTEK is it's smarter than the DC-DC converter for things like desulfation.

How many insertion cycles is the D/C cut fuse rated for though? My worry would be if you're doing that regularly, you're liable to cause undue wear.

Do you leave the car for 1 month? It is needed only if you leave the car for one month or more. You can disable smart keys option for a while too.

It is pure copper, pretty soft. So, less than 100x should be fine, but  not too often. As long as you slide it straight, not crooked, it will be fine. 

[AisinW]

3 hours ago, Roy124 said:

Question for all you converts that use a CTEK charger or equivalent, even if you are using the car regularly, do you also use the CTEK for conditioning? 

I Don't recommends CTEK, NocoGenius5 is better build for the same price. It is more robust for any spike voltage and humidity. There is video teardown about CTEK and NOCO. The quality of charging are similar but the switch and water resistance are so different. 

I also think to buy a Noco Genius5 but for €75, it is close to half of new Battery €181.  I probably will just buy a new Yuasa original Toyota Battery instead.   

I never use external charger. Prius DCtoDC converter is smarter maintaining Battery without overcharging. It is already 6 years old, the voltage is 12.5 After long jorney 30mins or more and close to 12.3-12.4V after 2 days or more. It is not new, but not sure how much longer it will be fine.  I probably just by battery tester instead for €35. 

https://youtu.be/rFRXXR0e0Xk

[Catlover]

P, see how you go once your Battery is fully charged by the CTEK, but 5 year is good for a batter, so if it doesn’t respond well to the charge be prepared to buy a new Battery. Hope it goes ok for you though.

[AisinW]

Thanks, my Battery on my 06 Prius was 7 years 9 months before it goes flat if I park more than 6 hours. But the Battery reading when IGN on was indeed only 10.8V. 

Now is currently 11.5-12V when IGN is on.  I don't want to spend money if i don't have to, but do not want to be stuck either. I have jumper cable as a backup. 

[Redjohn]

On 12/22/2021 at 4:07 PM, FlatYaris said:

Toyota have more or less admitted to me that the Yaris 12v battery isn't up to the job.  I would suggest steer clear of buying any Toyotas until they provide equipment that is.  A slight drop in sales may spur them into action. 

Well as a newbie to this post I can see by reading all the 12volt Battery problems in the mk4 Yaris hybrid, that indeed Toyota have got this wrong. I own a 2021 Yaris launch edition hybrid from new with a 1.5 ltr engine and  I too have a 12v Battery problem. First time nov 21 the AA report Battery not holding charge (advise replacement), Toyota garage nothing wrong just keep going on a drive of 30 mins at least twice a week. Jan 2022 same thing AA report battery need replacing. Booked in for battery check (note if battery ok £108 please) don’t think so!!!!!  I do a 15 min drive twice (sometimes four) times a week with at least a 100mile if not more journey once a month. AA guy told me that should be enough to charge the battery. Well what’s going to happen when I go on holiday for two weeks parked up at the airport!!!!! Flat battery I think would be a fair guess.  Toyota have a very good record of being reliable (tick) but as it is looking now that it’s seems to be the 12volt battery that’s going to let the brand down. Modern tec need some back up and the 12v battery dose seem not to be doing the job especially when these cars are now £20,000 upwards. Come on Toyota do the right thing and give us a battery that can do the job (and not cause us owners undue pain and hardship in waiting several +hours for a nice AA man who can get you going) this is now my 4th Yaris and the most expensive one yet (with problems) the other 3 nothing untoward and very reliable 😵‍💫

[AisinW]

 

1 hour ago, Redjohn said:

Well as a newbie to this post I can see by reading all the 12volt battery problems in the mk4 Yaris hybrid, that indeed Toyota have got this wrong. I own a 2021 Yaris launch edition hybrid from new with a 1.5 ltr engine and  I too have a 12v battery problem. First time nov 21 the AA report battery not holding charge (advise replacement), Toyota garage nothing wrong just keep going on a drive of 30 mins at least twice a week. Jan 2022 same thing AA report battery need replacing. Booked in for battery check (note if battery ok £108 please) don’t think so!!!!!  I do a 15 min drive twice (sometimes four) times a week with at least a 100mile if not more journey once a month. AA guy told me that should be enough to charge the battery. Well what’s going to happen when I go on holiday for two weeks parked up at the airport!!!!! Flat battery I think would be a fair guess.  Toyota have a very good record of being reliable (tick) but as it is looking now that it’s seems to be the 12volt battery that’s going to let the brand down. Modern tec need some back up and the 12v battery dose seem not to be doing the job especially when these cars are now £20,000 upwards. Come on Toyota do the right thing and give us a battery that can do the job (and not cause us owners undue pain and hardship in waiting several +hours for a nice AA man who can get you going) this is now my 4th Yaris and the most expensive one yet (with problems) the other 3 nothing untoward and very reliable 😵‍💫

The main culprit may be the dealership itself that don't want to investigate the problem.  2 weeks is nothing, the Battery should hold the charge at least 1 month.  Per TSB, removing 12V negative terminal  is necessary only if it is parked more than 1 month and start the car 30 minutes every 2 months. There must be a defective Battery or a parasitic drain somewhere. I heard from other forums that 2022 Yaris  has problems with the 12V pretty often. It seems like bad batch of AGM batteries in Yaris. 

I suggest you press the dealerhip and bother them as much as possible until they replace the Battery. It is possible that it has internal 12V defect.  

[Redjohn]

12 hours ago, AisinW said:

 

The main culprit may be the dealership itself that don't want to investigate the problem.  2 weeks is nothing, the battery should hold the charge at least 1 month.  Per TSB, removing 12V negative terminal  is necessary only if it is parked more than 1 month and start the car 30 minutes every 2 months. There must be a defective battery or a parasitic drain somewhere. I heard from other forums that 2022 Yaris  has problems with the 12V pretty often. It seems like bad batch of AGM batteries in Yaris. 

I suggest you press the dealerhip and bother them as much as possible until they replace the battery. It is possible that it has internal 12V defect.  

Thanks for the info AisinW, thought as much as anybody with some knowledge of cars etc would come to the same conclusion!!!  The dealership are investigating this Battery problem, but have been directed by Toyota GB to follow the correct procedure. First  the Battery to be checked, if found low then charge for 10 hours, re-test if still defective a replacement can be fitted , so far, fair enough. But as it must seem that it’s more of, as you said “a bad batch of AGM battery’s ” these are on order-frozen (short of stock I guess) for the parts dept. As they can’t say when one will be available, could be 3 weeks/3 months!!!   So I enquired as to fitting a spare Battery till one is available, can’t do that as a shortage of said item. So basically you have a modern car costing upwards of 20 grand that you can’t use. Well I never!!!!!  Courtesy car at the moment, but only till tests have been carried out, then it’s over to Toyota to supply a hire car till whenever!!!!!!   What’s going on in this world, come on Toyota get the stock and replace the batteries as you are supposed to be one of the best car manufactures going, but seems lacking on the after sales side.

[Roy124]

If you have a voltmeter take and log a daily Battery voltage.  If you don't use the car for 3-4 days you will have a good idea of the voltage drop.  Don't just do this once but over a month say.  In that month you might have a number of records showing a consistent drop.  Hard to argue against facts. 

[Catlover]

25 minutes ago, Redjohn said:

  What’s going on in this world, come on Toyota get the stock and replace the batteries as you are supposed to be one of the best car manufactures going, but seems lacking on the after sales side.

Toyota do not make the batteries. Maybe the manufacturer has been hit by covid and lot of their workforce not in….. production down. That could be the reality of what is going on in the world. And just because restrictions are being lifted next Thursday in the uk, that doesn’t reflect what mess covid is still causing in other countries, particularly Asia.